Image pickup apparatus, solid-state image pickup device, and image pickup method

ABSTRACT

A solid-state image pickup device including a lens, a first light receiving element, a second light receiving element, and an element separation area. The first light receiving element is configured to receive light from the lens. The second light receiving element is configured to receive light from the lens. The element separation area is between the first light receiving element and the second light receiving element. The lens has an optical axis, which is offset from a center of the element separation area.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.15/196,308 filed Jun. 29, 2016 which is a continuation of U.S. patentapplication Ser. No. 14/854,218 filed Sep. 15, 2015, now U.S. Pat. No.9,451,158 issued Sep. 20, 2016, which is a continuation of U.S. patentapplication Ser. No. 14/573,779 filed Dec. 17, 2014, now U.S. Pat. No.9,172,865 issued on Oct. 27, 2015, which is a continuation of U.S.patent application Ser. No. 13/637,734, filed Sep. 27, 2012, now U.S.Pat. No. 8,953,085 issued Feb. 10, 2015, which is the Section 371National Stage of PCT/JP2011/058863 filed Apr. 1, 2011, the entiretiesof which are incorporated herein to the extent permitted by law. Thisapplication claims the benefit of priority to Japanese PatentApplication No. 2010-089796, filed Apr. 8, 2010, which is incorporatedherein by reference in its entirety to the extent permitted by law.

The present invention relates to an image pickup apparatus andparticularly relates to an image pickup apparatus that performs a phasedifference detection, a solid-state image pickup device, an image pickupmethod, and a program that causes a computer to execute the method.

BACKGROUND ART

In recent years, an image pickup apparatus has been available, such as adigital still camera that generates a picked-up image by picking up animage of a subject such as a person and records this generated picked-upimage. Also, as this image pickup apparatus, to facilitate an imagepickup operation by a user, an image pickup apparatus provided with anauto focus (AF: Auto Focus) function for automatically performing afocus (focus point, focal point) adjustment at the time of image pickuphas been widely available.

For such an image pickup apparatus, for example, an image pickupapparatus that forms a pair of images by performing pupil division onlight that passes through an image pickup lens and measures an intervalbetween the formed images (detects a phase difference) to decide aposition of the image pickup lens is proposed (for example, see PTL 1.).This image pickup apparatus forms a pair of images by providing an imagesensor with a pixel for focus detection where a pair of light receivingelements are provided to one pixel and calculates a shift amount of thefocus by measuring an interval between the formed images. Then, thisimage pickup apparatus calculates a movement amount of the image pickuplens on the basis of the calculated shift amount of the focus andadjusts the position of the image pickup lens on the basis of thecalculated movement amount to effect focusing (focus adjustment).

According to the above-mentioned conventional technology, as both pixelsincluding the pixel for phase difference detection (focus detection) andthe pixel for picked-up image generation are provided to one imagesensor, it is not necessary to separately provide two sensors, i.e. asensor for focus detection and a sensor for picked-up image.

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication No.2000-305010 (FIG. 1)

SUMMARY OF INVENTION

However, regarding the above-mentioned conventional technology, theinventors have recognized that in the pixels for focus detection, as thetwo light receiving elements are irradiated with the lights subjected tothe pupil division at substantial equal amounts, in a case where thelight amount incident on each of the light receiving elements isrelatively low or a case of being excessive, a pair of images cannot beformed accurately. According to this, the amount of the shift of thefocus cannot be calculated accurately, and the accuracy of the focusadjustment may decrease.

Disclosed herein are one or more inventions that are configured toimprove an accuracy of the focus adjustment.

In an embodiment, an imaging device has a light sensor comprising twolight sensitive elements asymmetrically positioned about opposite sidesof a centerline of the light sensor.

In an embodiment, a solid state image pickup device include a lens, afirst light receiving element, a second light receiving element, and anelement separation area. The lens has an optical axis. The first lightreceiving element is configured to receive light from the lens. Thesecond light receiving element is configured to receive light from thelens. The element separation area is between the first light receivingelement and the second light receiving element. The optical axis of thelens is offset from a center of the element separation area.

In an embodiment, an image pickup apparatus includes an image sensor anda signal processing unit. The image sensor is configured to performphotoelectric conversion on incident light to generate an electricsignal. The image sensor includes a first pixel. The first pixelincludes (a) a lens having an optical axis, (b) a first light receivingelement configured to convert light from the lens into an electricsignal, (c) a second light receiving element configured to convert lightfrom the lens into an electric signal, and (d) an element separationarea between the first light receiving element and the second lightreceiving element. The signal processing unit is configured to generateimage data corresponding to electric signals from the first lightreceiving element and generate image data corresponding to electricsignals from the second light receiving element. The optical axis of thefirst pixel is offset from a center of the element separation area ofthe first pixel.

In an embodiment, a method for controlling a solid-state image pickupdevice includes generating a first electric signal and generating asecond electric signal. The first electric signal is generated via afirst light receiving element. The first light receiving element isconfigured to receive light from a lens of a pixel. The second electricsignal is generated via a second light receiving element. The secondlight receiving element is configured to receive light from the lens ofthe pixel. The pixel includes an element separation area between thefirst light receiving element and the second light receiving element. Anoptical axis of the lens is offset from a center of the elementseparation area.

In an embodiment, a method for controlling an image pickup apparatusincludes receiving a first electric signal from a first light receivingelement, receiving a second electric signal from a second lightreceiving element, and generating image data corresponding to electricsignals from the first light receiving element and the second lightreceiving element. The first light receiving element is configured toreceive light from a lens of a pixel. The second light receiving elementis configured to receive light from the lens of the pixel. The pixelincludes an element separation area between the first light receivingelement and the second light receiving element. The optical axis of thelens is offset from a center of the element separation area.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a configuration example of animage pickup apparatus according to a first embodiment.

FIG. 2A is a cross sectional view and FIG. 2B is a top view,schematically illustrating an example of an image pickup element.

FIGS. 3A and 3B includes cross sectional views, schematicallyillustrating examples of focus detection pixels according to the firstembodiment.

FIG. 4A is a top view schematically illustrating a focus detectionelement that is the same pixel as an existing focus detection elementand FIG. 4B illustrates light receiving amounts of light incident on thefocus detection element.

FIG. 5A is a top view schematically illustrating a focus detectionelement according to the first embodiment and FIG. 5B is a drawingillustrating an example of light receiving amounts of light incident onthe focus detection element.

FIGS. 6A and 6B are schematic diagrams illustrating an effect of lightreception by the focus detection element according to the firstembodiment.

FIGS. 7A, 7B, and 7C are top views, schematically illustrating focusdetection pixels according to the first embodiment.

FIGS. 8A and 8B are top views schematically illustrating focus detectionpixels according to the first embodiment.

FIGS. 9A and 9B are top views schematically illustrating focus detectionpixels according to the first embodiment.

FIG. 10 is a schematic diagram illustrating an example of an area wherethe focus detection pixels are arranged in an image sensor according tothe first embodiment.

FIG. 11 is a schematic diagram illustrating an example of a pixelarrangement in a focus detection area according to the first embodiment.

FIG. 12 is a schematic diagram illustrating an example of a pixelarrangement in a focus detection area according to the first embodiment.

FIG. 13 is a schematic diagram illustrating an example of a pixelarrangement in a focus detection area according to the first embodiment.

FIG. 14 is a schematic diagram illustrating an example of a pixelarrangement in a focus detection area according to the first embodiment.

FIG. 15 is a schematic diagram illustrating an example of a pixelarrangement in a focus detection area according to the first embodiment.

FIG. 16 illustrates a phase difference detection example at the time ofin-focus according to the first embodiment.

FIG. 17 illustrates a phase difference detection example at the time ofback focus according to the first embodiment.

FIG. 18 illustrates a phase difference detection example when the amountof light is relatively low or small according to the first embodiment.

FIG. 19 illustrates a phase difference detection example at the time ofsaturation of the light amount according to the first embodiment.

FIG. 20 is a flow chart illustrating a focus control procedure exampleby the image pickup apparatus according to the first embodiment.

FIG. 21A is a cross sectional view and FIG. 21B is a top viewschematically illustrating an example of a focus detection pixelaccording to a second embodiment.

FIGS. 22A and 22B are schematic diagrams illustrating examples of asignal line of the image sensor according to a third embodiment.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Hereinafter, devices and constructions embodying principles of thepresent invention(s) (herein referred to as embodiments) will bedescribed. The description will be carried out in the following order.

1. First Embodiment (image pickup control: an example of settingarrangement positions of a pair of light receiving elementsasymmetrical)

2. Second Embodiment (image pickup control: an example of adjusting anarrangement position of a micro lens)

3. Third Embodiment (image pickup control: an example of arranging twosignal lines)

1. First Embodiment Functional Configuration Example of Image PickupApparatus

FIG. 1 is a block diagram illustrating a configuration example of animage pickup apparatus 100 according to a first embodiment. This imagepickup apparatus 100 is provided with a lens unit 110, an image sensor200, a signal processing unit 130, a control unit 140, a drive unit 150,a storage unit 160, and a display unit 170.

It should be noted that this image pickup apparatus 100 is configured toperform an AF (Auto Focus) control based on a phase difference detectionsystem. This phase difference detection system is a system in which animage interval of subjects separated by two lenses is measured, and aposition of an image pickup lens is decided on the basis of the positionwhere this image interval becomes a predetermined value.

The lens unit 110 is composed of a plurality of image pickup lenses suchas a focus lens and a zoom lens and is configured to supply incidentlight from a subject which is input via these lenses to the image sensor200. This lens unit 110 is adjusted so that the focus (which is alsoreferred to as focus point or focal point) with respect to the subjectis effected while positions of the plurality of image pickup lenses areadjusted by the drive unit 150.

The image sensor 200 is an image pickup element that performsphotoelectric conversion on the incident light from the subject passingthrough the lens unit 110 on the basis of a control by the control unit140 into an electric signal. This image sensor 200 is composed of apixel that generates an electric signal (image pickup signal) forgenerating a picked-up image and a pixel that generates an electricsignal (focus adjustment signal) for adjusting the focus. This imagesensor 200 supplies the electric signal generated through thephotoelectric conversion to the signal processing unit 130. It should benoted that the image sensor 200 is supposed to have a substantiallyrectangular shape. Also, the pixel that generates the image pickupsignal (image pickup pixel) will be described in detail with respect toFIGS. 2A and 2B. Also, the pixel that generates the focus adjustmentsignal (focus detection pixel) will be described in detail by usingFIGS. 3 to 9. Also, this image sensor 200 will be described in detail byusing FIGS. 10 to 15. It should be noted that the image sensor 200 is anexample of an image pickup element described in the scope of claims.Also, the focus adjustment signal is an example of a focus detectionsignal described in the scope of claims.

The signal processing unit 130 is configured to apply various signalprocessings on the electric signal supplied from the image sensor 200.For example, this signal processing unit 130 generates picked-up imagedata on the basis of the image pickup signal supplied from the imagesensor 200 and supplies this generated picked-up image data to thestorage unit 160 to be recorded in the storage unit 160 as the imagefile. Also, the signal processing unit 130 supplies the generatedpicked-up image data to the display unit 170 to be displayed as thepicked-up image. Also, this signal processing unit 130 generates imagedata for focus adjustment on the basis of the focus adjustment signalsupplied from the image sensor 200 and supplies this generated imagedata for focus adjustment to the control unit 140.

The control unit 140 is configured to calculate a shift amount of thefocus (defocus amount) on the basis of the image data for focusadjustment supplied from the signal processing unit 130 and calculate amovement amount of the image pickup lens of the lens unit 110 on thebasis of the calculated defocus amount. Then, this control unit 140supplies information related to the calculated movement amount of theimage pickup lens to the drive unit 150. That is, this control unit 140performs an in-focus determination by calculating the shift amount ofthe focus, generates information related to the movement amount of theimage pickup lens on the basis of this in-focus determination result,and supplies this generated information to the drive unit 150. It shouldbe noted that the control unit 140 is an example of a determination unitdescribed in the scope of claims.

The drive unit 150 is configured to move the image pickup lens of thelens unit 110 on the basis of the information related to the movementamount of the image pickup lens supplied from the control unit 140.

The storage unit 160 is configured to store the picked-up image datasupplied from the signal processing unit 130 as an image file.

The display unit 170 is configured to display the picked-up image datasupplied from the signal processing unit 130 as a picked-up image (forexample, a through-the-lens image).

Configuration Example of Image Pickup Pixel

FIG. 2A is a cross sectional view and FIG. 2B is a top viewschematically illustrating an example of an image pickup pixel 310. Theimage pickup pixel 310, illustrated in FIGS. 2A and 2B, is an example ofa pixel (image pickup pixel) that generates an image pickup signal amongthe respective pixels constituting the image sensor 200.

FIG. 2A schematically illustrates a cross sectional configuration of theimage pickup pixel 310 in the image sensor 200.

This image pickup pixel 310 is provided with a planarizing film 312, aninsulating film 313, and a light receiving element 314. Also, a microlens 311 that condenses light incident on the image pickup pixel 310 tothe light receiving element 314 is provided on the image pickup pixel310.

It should be noted that herein, the light passing through the micro lens311 is in focus on a light receiving plane of the light receivingelement 314.

The micro lens 311 is arranged so that the center of the micro lens 311and the center of the light receiving element 314 are located on a sameaxis. Also, this micro lens 311 is arranged so that a light receivingposition of the light receiving element 314 and a position of a focus F1of the micro lens 311 are on a same plane.

The planarizing film 312 and the insulating film 313 are layers composedof a transparent insulating material which cover the light receivingplane of the light receiving element 314. It should be noted that acolor filter of red, green, or blue is arranged between the planarizingfilm 312 and the insulating film 313 in an actual apparatus, butaccording to the first embodiment, for the sake of simplicity in thedescription, the image sensor 200 that detects monochrome (brightness oflight) is supposed.

The light receiving element 314 is configured to generate an electricsignal at an intensity in accordance with the amount of the receivedlight by converting the received light into the electric signal(photoelectric conversion). This light receiving element 314 iscomposed, for example, of a photo diode (PD: Photo Diode).

Here, the light incident on the light receiving element 314 (incidentlight) will be described by using FIG. 2A. FIG. 2A schematicallyillustrates light incident on the micro lens 311 at an angle in parallelto an axis L1 which is parallel to the optical axis passing through thecenter position of the micro lens 311 (light irradiated in a range R1illustrated in FIG. 2A) among the light incident on the light receivingelement 314. Also, FIG. 2A schematically illustrates light incident onthe micro lens 311 (light incident in ranges R2 and R3 illustrated inFIG. 2A) at an angle inclined by predetermined angles with respect tothe axis L1 (angles −α and α illustrated in FIG. 2A). It should be notedthat the axis L1 is an example of an optical axis of the micro lensdescribed in the scope of claims.

The light incident in the range R1 (range R1 incident light) is lightincident on the micro lens 311 at an angle in parallel to the axis L1.This range R1 incident light is condensed by the micro lens 311 at thefocus F1.

The lights incident in the ranges R2 and R3 (the range R2 incident lightand the range R3 incident light) are lights incident on the micro lens311 at an angle inclined by predetermined angles (−α and α) with respectto the axis L1. These range R2 incident light and range R3 incidentlight are incident lights illustrating examples of light incident on themicro lens 311 at an angle inclined by predetermined angles with respectto the axis L1. These range R2 incident light and range R3 incidentlight are condensed in a predetermined area in the light receiving planeof the light receiving element 314.

FIG. 2B illustrates an example of an irradiation position of the lightincident on the image pickup pixel 310 illustrated in FIG. 2A.

It should be noted that in this FIG. 2B, a description will be givenwhile an xy coordinate system is supposed in which an intersecting pointof the axis L1 parallel in an optical axis direction passing through thecenter position of the micro lens 311 and the light receiving plane ofthe light receiving element 314 is set as an origin, a long side in theimage sensor 200 is set as an x axis, and a narrow side thereof is setas the y axis. Also, similarly also with respect to an xy coordinatesystem which will be described below, a description will be given whilethe xy coordinate system is supposed in which the intersecting point ofthe axis parallel to the optical axis passing through the centerposition of the micro lens and the light receiving plane of the lightreceiving element is set as the origin, the long side in the imagesensor 200 is set as the x axis, and the narrow side thereof is set asthe y axis.

In this FIG. 2B, components except for a light distribution area A3 arethe same as those illustrated in FIG. 2A, the same reference symbols asthose of FIG. 2A are assigned, and a description herein will be omitted.

The light distribution area A3 is an area where the light receivingplane of the light receiving element 314 is irradiated with the incidentlight on the micro lens 311. As illustrated in FIG. 2A, the lightirradiated on this light distribution area A3 (irradiation light)becomes light having a larger incident angle on the micro lens 311 asbeing away from the axis L1.

Here, the irradiation light in the light distribution area A3 will bedescribed. This is generated because the lens unit 110 is a telecentricoptical system or due to a phenomenon called marginal illuminationdecrease of the micro lens itself (for example, cosine fourth-powerlaw). For example, a consideration is given of the marginal illuminationdecrease of the micro lens itself in a case where α illustrated in FIG.2A is set as 32 degrees. In this case, the light amount on the lightreceiving plane of the incident light that is incident at the angle α(32 degrees) is substantially half of the light amount in the area wherethe light is parallel to the optical axis (focus F1). That is, in theirradiation light in the light receiving element 314, the light in thevicinity of the center of the light receiving element 314 (in thevicinity of the axis L1) is the strongest and weakens as being closer tothe end portion from the center of the light receiving element 314.

Configuration Example of Focus Detection Pixel

FIGS. 3A and 3B are cross sectional views schematically illustrating anexample of a focus detection pixel according to the first embodiment.FIG. 3A illustrate cross sectional views of a focus detection pixel 490and FIG. 3B illustrates a focus detection pixel 410 having a differentconfiguration from the focus detection pixel in the conventional imagepickup apparatus. These focus detection pixels 410 and 490 are examplesof pixels that generate focus adjustment signals (focus detectionpixels) among the respective pixels constituting the image sensor 200.It should be noted that an arrangement configuration of the focusdetection pixels in the image sensor 200 will be described in detailwith reference to FIG. 11 to FIG. 15.

It should be noted that according to the first embodiment, the microlenses 311 in the focus detection pixels 410 and 490 are set to be thesame as the micro lens 311 of the image pickup pixel 310 illustrated inFIGS. 2A and 2B.

Also, according to the first embodiment, the size of the entire pixel ofeach of the focus detection pixels 410 and 490 is the same as the sizeof the image pickup pixel 310 illustrated in FIGS. 2A and 2B. Also,according to the first embodiment, in each of the focus detection pixels410 and 490, the center of the focus detection and the axis L1 are setto be located on the same line.

FIG. 3A schematically illustrates a cross sectional configuration of thefocus detection pixel 490. In FIG. 3A, a cross sectional configurationis illustrated in a case where the left and right direction of FIG. 3Ais set as the narrow direction of the light receiving element in thefocus detection pixel 490.

It should be noted that as the incident light of the focus detectionpixels 410 and 490 is similar to that of FIG. 2A, only a range R1incident light is illustrated, and an illustration of a range R2incident light and a range R3 incident light that are examples of theincident light at an angle inclined by a predetermined angle will beomitted.

It should be noted that in FIG. 3A, configurations except for a firstlight receiving element 491, a second light receiving element 492, andan element separation area 493 are the same as the respective componentsof the image pickup pixel 310 illustrated in FIG. 2A, and a descriptionherein will therefore be omitted while assigning the same referencesymbols of FIG. 2A.

The first light receiving element 491 is a light receiving element thatforms a pair with the second light receiving element 492 and isconfigured to receive one of the two incident lights subjected to thepupil division. This first light receiving element 491 generates anelectric signal in accordance with the amount of received light byconverting the received light into an electric signal (photoelectricconversion) similarly as in the light receiving element 314 illustratedin FIG. 2A. Also, this first light receiving element 491 is a lightreceiving element having the same size and performance as those of thesecond light receiving element 492. It should be noted that as the focusdetection pixels 410 and 490 having the same size as the image pickuppixel 310 are provided with two light receiving elements, with regard tothe area, the area of the plane for receiving the light of the firstlight receiving element 491 is smaller than or equal to the half ascompared with the light receiving element 314 of the image pickup pixel310.

The second light receiving element 492 is a light receiving element thatforms the pair with the first light receiving element 491 and isconfigured to receive the other one of the two incident lights subjectedto the pupil division (light different from the light received by thefirst light receiving element 491). A function of this second lightreceiving element 492 is similar to the function of the first lightreceiving element 491, and a description herein will therefore beomitted.

The element separation area 493 is an insulating area located betweenthe first light receiving element 491 and the second light receivingelement 492 and is an area for separating so that the first lightreceiving element 491 and the second light receiving element 492 are notcontacted with each other. This element separation area 493 isconstructed between the first light receiving element 491 and the secondlight receiving element 492 so that the first light receiving element491 and the second light receiving element 492 are located in parallelto each other. Also, this element separation area 493 is constructed sothat the first light receiving element 491 and the second lightreceiving element 492 are located at an equal distance from the axis L1.For example, while a plane including the axis L1 is set as a symmetricalplane, the element separation area 493 is constructed so that the firstlight receiving element 491 and the second light receiving element 492are symmetrical to each other.

That is, in the focus detection pixel 490, the axis L1 is located at thecenter of the element separation area 493. Also, as the center of thefocus detection pixel 490 is coincided with the axis L1, the first lightreceiving element 491 and the second light receiving element 492 areconstructed to be located at an equal distance from the center of thefocus detection pixel 490.

It should be noted that according to the first embodiment, an intervalbetween the first light receiving element 491 and the second lightreceiving element 492 by this element separation area 493 is set as thenarrowest interval at which when the focus detection pixel isconstructed, the first light receiving element 491 and the second lightreceiving element 492 can be constructed so as not to contact with eachother.

FIG. 3B schematically illustrates a cross sectional configuration of thefocus detection pixel 410. In FIG. 3B, a cross sectional configurationin a case where the left and right direction of FIG. 3B is set as thenarrow direction of the light receiving element in the focus detectionpixel 410 is illustrated. It should be noted that cross sectionalconfigurations of focus detection pixels 420 to 480 illustrated in FIGS.7 to 9 are similar to that of the focus detection pixel 410, andtherefore the focus detection pixel 410 will be described herein, and adescription of the focus detection pixels 420 to 480 will be omitted.

It should be noted that in FIG. 3B, a first light receiving element 401,a second light receiving element 402, and components except for anelement separation area 403 are the same as or substantially similar tothe respective components of the image pickup pixel 310 illustrated inFIG. 2A, and a description herein will therefore be omitted whileassigning the same reference symbols. Also, the first light receivingelement 401, the second light receiving element 402, and the elementseparation area 403 are similar to the first light receiving element491, the second light receiving element 492, and the element separationarea 493 illustrated in FIG. 3A, and a description herein will thereforebe omitted.

The sizes of the first light receiving element 401, the second lightreceiving element 402, and the element separation area 403 in the focusdetection pixel 410 illustrated in FIG. 3B are the sizes of the firstlight receiving element 491, the second light receiving element 492, andthe element separation area 493 of the focus detection pixel 490 of FIG.3A. That is, these focus detection pixel 410 and focus detection pixel490 are different only in the light receiving plane of the lightreceiving element and the arrangement position of the light receivingelement on the same plane. For this reason, in FIG. 3B, only thearrangement position of the first light receiving element 401, thesecond light receiving element 402, and the element separation area 403will be described, and other descriptions will be omitted.

In this focus detection pixel 410, the second light receiving element402 is constructed at a position where the end portion on the side ofthe element separation area 403 of the second light receiving element402 tangent to the axis L1. On the other hand, with regard to the lightreceiving element 401, as compared with the end portion on the side ofthe element separation area 403 of the second light receiving element402, the end portion on the side of the element separation area 403 ofthe light receiving element 401 is far from the axis L1. That is, in thefocus detection pixel 410, the first light receiving element 401 and thesecond light receiving element 402 are constructed so that with respectto the plane including the axis L1, the first light receiving element401 and the second light receiving element 402 are set to be asymmetric.It should be noted that the first light receiving element 401 and thesecond light receiving element 402 is an example of a pair of lightreceiving elements described in the scope of claims.

As illustrated in FIG. 3B, by arranging the first light receivingelement 401 and the second light receiving element 402 asymmetric withrespect to the axis L1, a part of the irradiation light in the vicinityof the axis L1 of the focus detection pixel 410 can be incident on thelight receiving plane of the second light receiving element 492.

Light Receiving Example of Focus Detection Pixel 490

FIG. 4A is a top view schematically illustrating the focus detectionpixel 490 and FIG. 4B is a diagram illustrating an example of a lightreceiving amount of the light incident on the focus detection pixel 490.

FIG. 4A illustrates an irradiation position example of the lightincident on the focus detection pixel 490, illustrated in FIG. 3A.

It should be noted that components except for light distribution area A1and light distribution area A2 are similar to those illustrated in FIG.2B and FIG. 3A, and a description herein will therefore be omitted whileassigning the same reference symbols. Also, in FIG. 4B, the lightdistribution area A1 and the light distribution area A2 are representedby dotted circles.

The light distribution area A1 is an area representing a region thatreceives a relatively small amount of light since a great portion oflight in that area is irradiated on the element separation area 493.That is, this light distribution area A1 is an area where an angle ofthe light with respect to the axis L1 is small (non-telecentric lightclose to parallel rays of light (telecentric light)). As described inFIG. 2B, the light irradiated with the light receiving planesignificantly decreases as being away from the axis L1 (focus F1) due toa marginal illumination decrease or the like. That is, the irradiationlight in the light distribution area A1 has a larger light amount ascompared with the irradiation light in the light distribution area A2 onan outer side of the light distribution area A1. However, a large partof the irradiation light in this light distribution area A1 isirradiated on the element separation area 493, and therefore only a partthereof is irradiated on the first light receiving element 491 and thesecond light receiving element 492. That is, a large part of theirradiation light in this light distribution area A1 is irradiated onthe element separation area 493, and thus the light used for thephotoelectric conversion in the first light receiving element 491 andthe second light receiving element 492 is small.

The light distribution area A2 is an area on an outer side of the lightdistribution area A1 and is an area where the light incident on themicro lens 311 at an angle larger than the incident angle with respectto the axis L1 of the irradiation light in the light distribution areaA1 (non-telecentric light at an angle largely different from parallelrays of light) is irradiated. The irradiation light in this lightdistribution area A2 has a smaller light amount as compared with theirradiation light in the light distribution area A1. For that reason,the light receiving amounts in the first light receiving element 491 andthe second light receiving element 492 (total amount of irradiatedlights) are supposed to be smaller than the light amount of theirradiation light in the element separation area 493 depending on thewidth of the light distribution area A1.

As illustrated in this FIG. 4A, the first light receiving element 491and the second light receiving element 492 receive the light irradiatedon the area away from the axis L1 to some extent (area on the outer sideof the light distribution area A1). That is, on the first lightreceiving element 491 and the second light receiving element 492, thelight whose light amount per area is weaker than the light irradiated onthe light distribution area A1 (light at a larger angle than the lightirradiated on the light distribution area A1) is irradiated.

FIG. 4B illustrates a graph representing an example of light receivingamounts of the first light receiving element 491 and the second lightreceiving element 492 (total amount of the irradiation lights). Thegraph in FIG. 4B indicates bar graphs representing a light receivingamount in the first light receiving element 491 (light receiving amountB1), a light receiving amount in the second light receiving element 492(light receiving amount B2), and a total amount of the irradiationlights (irradiation amount B3) in the element separation area 493 whilethe vertical axis is set as the light receiving amount.

It should be noted that in FIG. 4B, as an example, a case is supposedand described in which the light amount of the irradiation light in thelight distribution area A1 is extremely large, and on the other hand,the light amount of the irradiation light in the light distribution areaA2 is relatively small.

The light receiving amount B1 and the light receiving amount B2 arelight receiving amounts in the first light receiving element 491 and thesecond light receiving element 492. In these light receiving amount B1and light receiving amount B2, it is illustrated that the first lightreceiving element 491 and the second light receiving element 492 arearranged at the symmetrical positions with respect to the axis L1, andtherefore the light receiving amounts of the light receiving amount B1and the light receiving amount B2 are equal to each other.

The irradiation amount B3 is a light amount irradiated on the elementseparation area 493. As an example, for this irradiation amount B3, itis illustrated that the light amount of the irradiation light in theelement separation area 493 is larger than the light amount of theirradiation light in the first light receiving element 491 and thesecond light receiving element 492. For example, in a case where thelens unit 110 is a telecentric optical system as well as the elementseparation area 493 is wide to some extent, and also, the micro lens 311and the light receiving element are proximal to each other, it isconceivable that the light amount of the irradiation light in theelement separation area 493 becomes extremely large in this way.

In this manner, in the focus detection pixel 490, although the lightamount of the irradiation light in the element separation area 493becomes extremely large, the irradiation light in the light distributionarea A1 is hardly used for the photoelectric conversion in the firstlight receiving element 491 and the second light receiving element 492.

Light Receiving Example of the Focus Detection Pixel 410

FIG. 5A is a top view schematically illustrating the focus detectionpixel 410 and FIG. 5B is a drawing illustrating an example of the lightreceiving amount of the light incident on the focus detection pixel 490according to the first embodiment.

FIG. 5A illustrates an irradiation position example of the lightincident on the focus detection pixel 410 illustrated in FIG. 3B.

It should be noted that components except for the first light receivingelement 401, the second light receiving element 402, and the elementseparation area 403 are similar to those illustrated in FIG. 2B, and adescription herein will therefore be omitted while assigning the samereference symbols of FIG. 2B.

As illustrated in this FIG. 5A, in the focus detection pixel 410, thesecond light receiving element 402 is irradiated with the right half ofthe irradiation light in the light distribution area A1. That is, in thefocus detection pixel 410, among the light incident on the lightdistribution area A1, the light irradiated on the right half of thelight distribution area A1 (on the plus side on the x axis) from thedirection of the left side of the micro lens 311 (on the minus side onthe x axis) is received in the second light receiving element 402. Onthe other hand, the element separation area 403 is irradiated with thelight collected in the vicinity of the focus F1 from the right side ofthe micro lens 311 (on the plus side on the x axis) among the lightincident on the focus F1 similarly as in the focus detection pixel 490.

Also, the irradiation light in the light distribution area A2 isincident on the first light receiving element 401 and the second lightreceiving element 402 similarly as in the focus detection pixel 490.However, in the focus detection pixel 410, the light incident on thelight receiving element 401 is smaller than the light incident on thesecond light receiving element 402.

FIG. 5B is a graph illustrating an example of light receiving amounts ofthe positions of the first light receiving element 401 and the secondlight receiving element 402 (total amount of the irradiation lights).While the vertical axis is set as the light receiving amount, the graphin FIG. 5B indicates bar graphs representing a light receiving amount inthe first light receiving element 401 (light receiving amount B4), alight receiving amount in the second light receiving element 402 (lightreceiving amount B5), and the total amount of the irradiation lights(irradiation amount B6) in the element separation area 403. Also, inthis graph, as comparison targets of the light receiving amount B4, thelight receiving amount B5, and the irradiation amount B6, the bar graphsrepresenting the light receiving amount B1, the light receiving amountB2, and the irradiation amount B3 illustrated in FIG. 4B areillustrated.

Here, the light receiving amount of the focus detection pixel 410 willbe described while being compared with the light receiving amount of thefocus detection pixel 490.

The light receiving amount B4 indicates the light receiving amount ofthe first light receiving element 401 in the focus detection pixel 410.This light receiving amount B4 slightly decreases as compared with alight receiving amount in the first light receiving element 491 in thefocus detection pixel 490 (light receiving amount B1). As illustrated inFIG. 5A, in the light receiving element 401, this decrease occurs as thelight receiving amount of the irradiation light in the lightdistribution area A2 decreases.

The light receiving amount B5 indicates the light receiving amount ofthe second light receiving element 402 in the focus detection pixel 410.This light receiving amount B5 significantly increases as compared withthe light receiving amount in the second light receiving element 492(light receiving amount B2) in the focus detection pixel 490. Asillustrated in FIG. 5A, this increase occurs as the irradiation light onthe left half of the light distribution area A1 is received by thesecond light receiving element 492.

The irradiation amount B6 indicates the total amount of the irradiationlights in the element separation area 403. This irradiation amount B6significantly decreases as compared with the total amount of theirradiation lights in the element separation area 493 (the irradiationamount B3). This decrease occurs while the second light receivingelement 402 becomes adjacent to the axis L1, the second light receivingelement 402 is irradiated with the irradiation light on the right halfof the light distribution area A1.

In this manner, in the focus detection pixel 410, as the second lightreceiving element 402 is adjacent to the axis L1, the incident lightfrom the left side of the micro lens 311 among the lights subjected tothe pupil division can efficiently be incident on the light receivingelement.

It should be noted that herein, the example has been described in whichthe axis L1 is located at the end portion on the side of the elementseparation area 403 of the second light receiving element 402, but thepresent invention is not limited to this. With regard to the firstembodiment, it suffices as long as the positions of the first lightreceiving element 401 and the second light receiving element 402 areadjusted so that the second light receiving element 402 is irradiatedwith the light irradiated in the vicinity of the axis L1 of the lightreceiving plane (in the vicinity of the focus F1). That is, a case isconceivable in which the positions of the first light receiving element401 and the second light receiving element 402 are adjusted so that theaxis L1 is located between the center of the element separation area 403and the end portion on the side of the element separation area 403 ofthe second light receiving element 402.

Effect Example of the Focus Detection Pixel 410

FIGS. 6A and 6B are schematic diagrams, illustrating an effect of thelight reception by the focus detection pixel 410 according to the firstembodiment.

FIG. 6A illustrates a graph representing examples of the light receivingamounts of the positions of the first light receiving element 401 andthe second light receiving element 402 in a case where the light amountincident on the focus detection pixel 410 is small or low. The graph inFIG. 6A includes bar graphs representing a light receiving amount in thefirst light receiving element 401 (light receiving amount B9) and alight receiving amount in the second light receiving element 402 (lightreceiving amount B10) while the vertical axis is set as the lightreceiving amount. Also, this graph indicates the bar graphs representinga light receiving amount in the first light receiving element 491 (lightreceiving amount B7) and a light receiving amount in the second lightreceiving element 492 (light receiving amount B8) in a case where thesame incident light is incident on the focus detection pixel 490 ascomparison targets of the light receiving amounts B9 and B10.

In FIG. 6A, a state is supposed in which as the light amount incident onthe focus detection pixel is small or low, the first light receivingelement 491 and the second light receiving element 492 of the focusdetection pixel 490 cannot generate electric signals.

The light receiving amount B7 indicates the light receiving amount inthe first light receiving element 491 of the focus detection pixel 490.This light receiving amount B7 indicates that the light receiving amountin the first light receiving element 491 is a light receiving amountlower than a light amount for a weak light detection limit by the lightreceiving element (weak light detection limit Th2). The first lightreceiving element 491 at this light receiving amount outputs an electricsignal indicating no light reception in the first light receivingelement 491 as an electric signal cannot be generated in the case of alight receiving amount lower than or equal to the weak light detectionlimit Th2 (for example, “0” among 256-gradation electric signals).

The light receiving amount B8 indicates the light receiving amount inthe second light receiving element 492 of the focus detection pixel 490.This light receiving amount B8 indicates that the light receiving amountin the second light receiving element 492 is a light receiving amountlower than the weak light detection limit Th2. The second lightreceiving element 492 at this light receiving amount outputs an electricsignal indicating no light reception in the second light receivingelement 492 similarly as in the first light receiving element 491 whoselight receiving amount is the light receiving amount B7.

The light receiving amount B9 and the light receiving amount B10indicate the light receiving amounts of the positions of the first lightreceiving element 401 and the second light receiving element 402 in thefocus detection pixel 410. In these light receiving amount B9 and thelight receiving amount B10, as described in FIGS. 5A and 5B, the lightreceiving amount in the second light receiving element 492 increases,and as a result, it is indicated that the light receiving amount of thesecond light receiving element 402 exceeds the weak light detectionlimit Th2. In this case, the light receiving element 401 outputs anelectric signal indicating no light reception and outputs an electricsignal indicating that the second light receiving element 492 receivesthe light (for example, “20” among the 256-gradation electric signals).

That is, in the focus detection pixel 490, even in a case where theincident light lower than the detection limit is irradiated, the focusdetection pixel 410 can detect the light amount as the light receivingamount higher than the weak light detection limit Th2 exists in thesecond light receiving element 402.

FIG. 6B illustrates a graph representing examples of light receivingamounts at the positions of the first light receiving element 401 andthe second light receiving element 402 in a case where the light amountincident on the focus detection pixel 410 is saturated. The graph inFIG. 6B indicates bar graphs representing a light receiving amount inthe first light receiving element 401 (light receiving amount B13) and alight receiving amount in the second light receiving element 402 (lightreceiving amount B14) while the vertical axis is set as the lightreceiving amount. Also, this graph indicates bar graphs representing alight receiving amount in the first light receiving element 491 (lightreceiving amount B11) and a light receiving amount in the second lightreceiving element 492 (light receiving amount B12) in a case where thesame indicant light is incident on the focus detection pixel 490 ascomparison targets for the light receiving amounts B13 and B14.

The light receiving amount B11 indicates the light receiving amount inthe first light receiving element 491 of the focus detection pixel 490.This light receiving amount B11 indicates that the light receivingamount in the first light receiving element 491 is a light receivingamount higher than the maximum light amount that can be detected by thelight receiving element (saturation detection limit Th1). The firstlight receiving element 491 at this light receiving amount cannot detecta difference of the light receiving amount higher than or equal to thesaturation detection limit Th1 and therefore outputs an electric signalindicating that the light reception in the first light receiving element491 is maximum (for example, “255” among the 256-gradation electricsignals).

The light receiving amount B12 indicates the light receiving amount inthe second light receiving element 492 of the focus detection pixel 490.This light receiving amount B8 indicates that the light receiving amountin the second light receiving element 492 is a light receiving amounthigher than the saturation detection limit Th1. The second lightreceiving element 492 at this light receiving amount outputs an electricsignal indicating that the light receiving amount is the maximum lightreception in the second light receiving element 492 similarly as in thefirst light receiving element 491 at the light receiving amount B11.

The light receiving amount B13 and the light receiving amount B14indicate the light receiving amounts at the positions of the first lightreceiving element 401 and the second light receiving element 402 of thefocus detection pixel 410. In the light receiving amount B13 and thelight receiving amount B14, as described in FIGS. 5A and 5B, it isindicated that the light receiving amount in the second light receivingelement 492 increases, and also the light receiving amount in the firstlight receiving element 491 decreases, and as a result, the lightreceiving amount of the first light receiving element 401 becomes lowerthan or equal to the saturation detection limit Th1.

That is, in the focus detection pixel 490, even in a case where theincident light higher than the detection limit is irradiated, in thelight receiving element 401, the light receiving amount becomes lowerthan the saturation detection limit Th1, and the focus detection pixel410 can detect a difference of the light amount.

Light Receiving Example of Focus Detection Pixels 420 to 480

FIGS. 7 to 9 are schematic drawings illustrating light receivingexamples of the light amounts incident on the focus detection pixels 420to 480 according to the first embodiment.

In these FIGS. 7 to 9, with regard to the focus detection pixels 420 to480, a difference from the focus detection pixel 410 illustrated in FIG.5A will be described.

Also, according to the first embodiment, in the focus detection pixels410 to 490, the light receiving element proximal to the optical axis ofthe micro lens 311 is supposed to be the second light receiving element402.

FIGS. 7A, 7B, and 7C are top views schematically illustrating the focusdetection pixels 420 to 440 according to the first embodiment.

As illustrated in FIG. 7A, while the origin of the xy coordinates is setas the rotation center, the focus detection pixel 420 is obtained byrotating clockwise the focus detection pixel 410 illustrated in FIG. 5Aby 180°. This focus detection pixel 420 can receive the light irradiatedfrom the right side of the micro lens 311 (on the plus side on the xaxis) on the left side of the light distribution area A1 (on the minusside on the x axis) in the second light receiving element 402. Thisfocus detection pixel 420 can efficiently receive the lights subjectedto the pupil division (lights divided on the plus side and the minusside on the x axis) in the left and right direction of the micro lens311 while being used together with the focus detection pixel 410.

As illustrated in FIG. 7B, while the origin of the xy coordinates is setas the rotation center, the focus detection pixel 430 is obtained byrotating clockwise the focus detection pixel 410 illustrated in FIG. 5Aby 270°. This focus detection pixel 430 can receive the light irradiatedfrom the bottom side of the micro lens 311 (on the minus side on the yaxis) to the top side of the light distribution area A1 (on the plusside on the y axis) in the second light receiving element 402.

As illustrated in FIG. 7C, while the origin of the xy coordinates is setas the rotation center, the focus detection pixel 440 is obtained byrotating clockwise the focus detection pixel 410 illustrated in FIG. 5Aby 90°. This focus detection pixel 440 can efficiently receive the lightirradiated from the top side of the micro lens 311 (on the plus side onthe y axis) to the bottom side of the light distribution area A2 (on theminus side on the y axis with respect to the axis L1 on the focus plane)in the second light receiving element 402. This focus detection pixel440 can efficiently receive the lights subjected to the pupil divisionin the up and down direction of the micro lens 311 (lights divided onthe plus side and the minus side on the y axis) while being usedtogether with the focus detection pixel 430.

FIGS. 8A and 8B are top views schematically illustrating the focusdetection pixels 450 and 460 according to the first embodiment.

As illustrated in FIG. 8A, while the origin of the xy coordinates is setas the rotation center, the focus detection pixel 450 is obtained byrotating clockwise the focus detection pixel 410 illustrated in FIG. 5Aby 315°. This focus detection pixel 450 can receive the light irradiatedfrom the lower right half of the micro lens 311 (bottom side of theareas divided by the light of y=x (on the minus side on the y axis)) tothe upper left half of the light distribution area A1 (top side of theareas divided by the light of y=x) in the second light receiving element402.

As illustrated in FIG. 8B, while the origin of the xy coordinates is setas the rotation center, the focus detection pixel 460 is obtained byrotating clockwise the focus detection pixel 410 illustrated in FIG. 5Aby 135°. This focus detection pixel 460 can receive the light irradiatedfrom the upper left half of the micro lens 311 (top side of the areasdivided by the light of y=x) to the lower right half of the lightdistribution area A1 (bottom side of the areas divided by the light ofy=x while the axis L1 is set as the center) in the second lightreceiving element 402. This focus detection pixel 460 can efficientlyreceive the lights subjected to the pupil division in the direction ofthe upper left and the lower right of the micro lens 311 (divided by theline of y=x) while being used together with the focus detection pixel450.

FIGS. 9A and 9B are top views schematically illustrating the focusdetection pixels 470 and 480 according to the first embodiment.

As illustrated in FIG. 9A, while the origin of the xy coordinates is setas the rotation center, the focus detection pixel 470 is obtained byrotating clockwise the focus detection pixel 410 illustrated in FIG. 5Aby 225°. This focus detection pixel 470 can receive the light irradiatedfrom the lower left half of the micro lens 311 (the bottom side of theareas divided by the line of y=−x) to the upper right half of the lightdistribution area A1 (the top side of the areas divided by the line ofy=−x) in the second light receiving element 402.

As illustrated in FIG. 9B, while the origin of the xy coordinates is setas the rotation center, the focus detection pixel 480 is obtained byrotating clockwise the focus detection pixel 410 illustrated in FIG. 5Aby 45°. This focus detection pixel 480 can receive the light irradiatedfrom the upper right half of the micro lens 311 (the top side of theareas divided by the line of y=−x) to the lower left half of the lightdistribution area A1 (the bottom side of the areas divided by the lineof y=−x while the axis L1 is set as the center) in the second lightreceiving element 402. This focus detection pixel 480 can efficientlyreceive the lights subjected to the pupil division in the direction ofthe lower left and the upper right of the micro lens 311 while beingused together with the focus detection pixel 470 (divided by the line ofy=−x).

In this manner, for the focus detection pixels in the image sensor 200,the focus detection pixel 490 where the arrangement position in thefocus detection pixels of a pair of light receiving elements issymmetric and the focus detection pixels 410 to 480 where thearrangement position in the focus detection pixels of a pair of lightreceiving elements is asymmetric are provided.

It should be noted that herein, the light receiving plane of the lightreceiving element is aligned with the focus plane of the micro lens 311,but the present invention is not limited to this. To accurately separatethe incident light on the micro lens 311, the light receiving plane ofthe light receiving element may also be set rearward with respect to thefocus plane.

Arrangement Example of Focus Detection Pixels in Image Sensor

FIG. 10 is a schematic diagram illustrating an example of an area wherethe focus detection pixels 410 to 490 are arranged in the image sensor200 according to the first embodiment.

FIG. 10 illustrates the image sensor 200 and the focus detection areas210, 230, 250, 270, and 290.

It should be noted that in FIGS. 10 to 14, a description will be givenwhile the center of the image sensor 200 is set as the origin, xy axesare supposed in which the left and right direction is set as the x axis,and the up and down direction is set as the y axis.

The focus detection areas 210, 230, 250, 270, and 290 are areasindicating examples of areas where the focus detection pixels 410 to 490are arranged. In this focus detection area, the image pickup pixel 310and any of the focus detection pixels 410 to 490 are arranged in apredetermined pattern. Also, in an area except for the focus detectionarea of the image sensor 200, only the image pickup pixel 310 isarranged.

These focus detection areas 290, 210, 230, 250, and 270 will bedescribed in detail by using FIGS. 11 to 14.

FIG. 11 is a schematic view illustrating an example of a pixelarrangement in the focus detection area 290 according to the firstembodiment.

It should be noted that in this FIG. 11 and subsequent figures, oneobtained by rotating clockwise the focus detection pixel 490 by 90° willbe referred to as focus detection pixel 495.

The focus detection area 290 is an area where the focus detection pixelsarea arranged in the vicinity of the center of the image sensor 200. Inthis focus detection area 290, for example, as illustrated in FIG. 11,the image pickup pixels 310 and the focus detection pixels 490 and 495are arranged in a predetermined pattern. This pattern is a pattern inwhich the image pickup pixels 310 are arranged so that the focusdetection pixels 490 and 495 can store image pickup data of the arrangedpixels. This predetermined pattern is a pattern in which, for example,as illustrated in FIG. 11, the image pickup pixels 310 are arranged onthe top, bottom, left, and right of the focus detection pixels 490 and495.

FIG. 12 is a schematic diagram illustrating an example of a pixelarrangement in the focus detection area 210 according to the firstembodiment.

The focus detection area 210 is an area where the focus detection pixelsin the vicinity of the center in the left end and the center in theright end of the image sensor 200 are arranged. In this focus detectionarea 210, for example, as illustrated in FIG. 12, the image pickuppixels 310 and the focus detection pixels 410, 420, and 495 are arrangedin a pattern similar to FIG. 11. Also, in this focus detection area 210,the focus detection pixels 410 and 420 that are the focus detectionpixels where the positions of one pair of the light receiving elementsare mutually different by 180 degrees are arranged are adjacentlyarranged.

FIG. 13 is a schematic view illustrating an example of a pixelarrangement in the focus detection area 230 according to the firstembodiment.

The focus detection area 230 is an area where the focus detection pixelsin the vicinity of the center in the upper end and the center in thelower end of the image sensor 200 are arranged. In this focus detectionarea 230, for example, as illustrated in FIG. 13, the image pickuppixels 310 and the focus detection pixels 430, 440, and 490 are arrangedin a pattern similar to FIG. 11. Also, in this focus detection area 230,the focus detection pixels 430 and 440 that are the focus detectionpixels where the positions of one pair of the light receiving elementsare mutually different by 180 degrees are adjacently arranged.

FIG. 14 is a schematic view illustrating an example of a pixelarrangement in the focus detection area 250 according to the firstembodiment.

The focus detection area 250 is an area where the focus detection pixelsin the vicinity of the left end in the upper end and the right end ofthe upper end of the image sensor 200 are arranged. In this focusdetection area 250, for example, as illustrated in FIG. 14, the imagepickup pixels 310 and the focus detection pixels 450, 460, and 490 arearranged in a pattern similar to FIG. 11. Also, in this focus detectionarea 250, the focus detection pixels 450 and 460 that are the focusdetection pixels where the positions of one pair of the light receivingelements are mutually different by 180 degrees are adjacently arranged.

FIG. 15 is a schematic view illustrating an example of a pixelarrangement in the focus detection area 270 according to the firstembodiment.

The focus detection area 270 is an area where the focus detection pixelsin the vicinity of the right end in the upper end and the left end inthe lower end of the image sensor 200 are arranged. In this focusdetection area 270, for example, as illustrated in FIG. 15, the imagepickup pixels 310 and the focus detection pixels 470, 480, and 490 arearranged in a pattern similar to FIG. 11. Also, in this focus detectionarea 270, the focus detection pixels 470 and 480 that are the focusdetection pixels where the positions of one pair of the light receivingelements are mutually different by 180 degrees are adjacently arranged.

In this manner, in accordance with the direction of the pupil division,by arranging the focus detection pixels 410 to 490 in the image sensor200, the first light receiving element 491 and the second lightreceiving element 492 can be efficiently irradiated with the light.

It should be noted that according to the first embodiment, the focusdetection areas 210, 230, 250, 270, and 290 are illustrated as anexample of the area where the focus detection pixels are arranged, butthe present invention is not limited to this. Any arrangement of thefocus detection pixels may suffice as long as the shift of the focus canbe detected, and, for example, a case of the arrangement in line in thex axis direction and the y axis direction is also conceivable.

Phase Difference Detection Example

FIGS. 16 to 19 are schematic diagrams illustrating phase differencedetection examples according to the first embodiment. In these FIGS. 16to 19, for the sake of convenience, a description will be given whilethe image sensor 200 is supposed in which the focus detection pixels 410and 420 are alternately arranged horizontally in line (for example, thex axis direction illustrated in FIG. 10) as the focus detection pixels.Also, in the examples illustrated in FIGS. 16 to 19, it is supposed thata light source (subject) exists at the center of the image sensor 200.

FIG. 16 illustrates a phase difference detection example at the time ofin-focus according to the first embodiment. In this drawing, a flowuntil the control unit 140 detects the shift of the focus on the basisof image data for focus adjustment generated from focus adjustmentsignals of the focus detection pixels 410 and 420 will be schematicallydescribed.

First, image data for focus adjustment that is generated by the signalprocessing unit 130 will be described.

Image data 611 is a graph schematically illustrating image datagenerated from the focus adjustment signal from the focus detectionpixel 410. In this image data 611, the horizontal axis is set as a pixelposition of the focus detection pixel 410 in the image sensor, and thevertical axis represents image data for focus adjustment having agradation indicating an intensity of the focus adjustment signal of thefocus detection pixel 410. This image data 611 indicates first lightreceiving element image data C1 and second light receiving element imagedata C2.

The first light receiving element image data C1 is image data generatedon the basis of the focus adjustment signal supplied by the lightreceiving element 401 of the focus detection pixel 410 (light receivingelement located on the minus side on the x axis). That is, this firstlight receiving element image data C1 indicates an intensitydistribution in the image sensor for the light incident from the rightside of the micro lens 311 (right side on the x axis of the micro lens311 illustrated in FIG. 5A). In FIG. 16, because of the in-focus state,the light from the subject is received by the light receiving element401 of the focus detection pixel 410 located in the vicinity of thecenter of the image sensor, and the focus adjustment signal is generatedon the basis of the amount of the received light.

The second light receiving element image data C2 is image data generatedon the basis of the focus adjustment signal supplied by the second lightreceiving element 402 of the focus detection pixel 410 (light receivingelement located on the plus side on the x axis). That is, this secondlight receiving element image data C2 indicates an intensitydistribution in the image sensor for the light incident from the leftside of the micro lens 311 (left side on the x axis of the micro lens311 illustrated in FIG. 5A). In FIG. 16, because of the in-focus state,similarly as in the first light receiving element image data C1, thelight from the subject is received by the second light receiving element402 of the focus detection pixel 410 located in the vicinity of thecenter of the image sensor, and the focus adjustment signal is generatedon the basis of the amount of the received light. Also, as described inFIG. 5, the focus adjustment signal having a larger gradation than thefocus adjustment signal of the light receiving element 401 is generatedby the second light receiving element 402.

Image data 612 is a graph schematically illustrating image datagenerated from the focus adjustment signal from the focus detectionpixel 420. In this image data 612, the horizontal axis is set as a pixelposition of the focus detection pixel 420 in the image sensor, and thevertical axis represents image data for focus adjustment having agradation indicating an intensity of the focus adjustment signal of thefocus detection pixel 420. This image data 612 indicates first lightreceiving element image data D1 and second light receiving element imagedata D2.

The first light receiving element image data D1 is image data generatedon the basis of the focus adjustment signal supplied by the lightreceiving element 401 of the focus detection pixel 420 (light receivingelement located on the plus side on the x axis). That is, this firstlight receiving element image data D1 indicates an intensitydistribution in the image sensor for the light incident from the leftside of the micro lens 311. In this FIG. 16, because of the in-focusstate, the light from the subject is received by the light receivingelement 401 of the focus detection pixel 420 located in the vicinity ofthe image sensor, and the focus adjustment signal is generated on thebasis of the amount of the received light.

The second light receiving element image data D2 is image data generatedon the basis of the focus adjustment signal supplied by the second lightreceiving element 402 of the focus detection pixel 420 (light receivingelement located on the minus side on the x axis). That is, this secondlight receiving element image data D2 indicates an intensitydistribution in the image sensor for the light incident from the rightside of the micro lens 311. In this FIG. 16, because of the in-focusstate, similarly as in the first light receiving element image data D1,the light from the subject is received by the second light receivingelement 402 of the focus detection pixel 420 located in the vicinity ofthe image sensor, and the focus adjustment signal is generated on thebasis of the amount of the received light. Also, as described in FIGS.5A and 5B, the focus adjustment signal having a larger gradation thanthe focus adjustment signal of the light receiving element 401 isgenerated by the second light receiving element 402.

Also, as the focus detection pixels 410 and 420 are alternately arrangedhorizontally in line, the first light receiving element image data C1and the first light receiving element image data D1 have substantiallythe same image position. Similarly, the second light receiving elementimage data C2 and the second light receiving element image data D2 havesubstantially the same image position.

In this manner, the signal processing unit 130 generates four pieces ofimage data for focus adjustment on the basis of the focus adjustmentsignals from the focus detection pixel 410 and the focus detection pixel420. Then, this signal processing unit 130 supplies the generated fourpieces of image data for focus adjustment to the control unit 140.

Next, an example of a focus detection in the control unit 140 will bedescribed.

Focus detection comparison image data 613 is a graph schematicallyillustrating two pieces of image data compared when the focus detectionis performed. In this focus detection comparison image data 613, thehorizontal axis is set as pixel positions of the focus detection pixel410 and the focus detection pixel 420 in the image sensor, and thevertical axis represents image data for focus adjustment having agradation indicating an intensity of the focus adjustment signal. Thisfocus detection comparison image data 613 indicates two pieces of imagedata to be compared in the focus detection (the second light receivingelement image data C2 and the first light receiving element image dataD2).

Here, an operation of the control unit 140 will be described withreference to the focus detection comparison image data 613. First, thecontrol unit 140 selects the two pieces of image data for focusadjustment from the four pieces of image data for focus adjustmentsupplied from the signal processing unit 130. That is, as this controlunit 140 performs the phase difference detection, the intensitydistribution of the light incident from the right side of the micro lens311 and the intensity distribution of the light incident from the leftside of the micro lens 311 are selected one each. This control unit 140can accurately detect the difference of the focus by using the focusadjustment image data where strength and weakness of the signal areclear. For this reason, the control unit 140 selects the image data forfocus adjustment having the strong signal (the second light receivingelement image data C2 and the first light receiving element image dataD2) among the four pieces of image data for focus adjustment.

Then, the control unit 140 detects a shift of images between the secondlight receiving element image data D2 and the second light receivingelement image data C2 (image interval E1). It should be noted that inFIG. 16, because of the in-focus state, the image interval E1 becomes aninterval and a positional relation between the position of the secondlight receiving element 402 of the focus detection pixel 410 whichreceives the strongest light amount and the light receiving element 401of the focus detection pixel 420 which receives the strongest lightamount.

The control unit 140 determines that the current state is the in-focusstate on the basis of the image interval E1 and supplies a signal formaintaining the position of the image pickup lens in the lens unit 110to the drive unit 150.

FIG. 17 illustrates a phase difference detection example at the time ofback focus according to the first embodiment.

Here, a description will be given while the light amount from thesubject is supposed to be the same as that of FIG. 16. That is, a stateexcept for the difference of the focus adjustment signal caused by theback focus is the same as FIG. 16.

Image data 621 is equivalent to the focus detection pixel 410 image data611 in FIG. 16, and image data 622 is equivalent to the image data 612in FIG. 16. Also, focus detection comparison image data 623 isequivalent to the focus detection comparison image data 613 in FIG. 16.

In this FIG. 17, a difference from the in-focus state illustrated inFIG. 16 will be described.

First, image data of the light receiving element that receives the lightincident from the left side of the image pickup lens will be described.In FIG. 17, because of the back focus, the light incident from the leftside of the image pickup lens is received after further proceeding onthe right side than at the time of in-focus. That is, the image data bythe second light receiving element 402 of the focus detection pixel 410(the second light receiving element image data C2 in FIG. 17) becomeslike image data obtained by shifting the image data at the time ofin-focus (the second light receiving element image data C2 in FIG. 16)to the right. Similarly, the image data by the light receiving element401 of the focus detection pixel 420 (the first light receiving elementimage data D1 in FIG. 17) becomes like image data obtained by shiftingthe image data at the time of in-focus (the first light receivingelement image data D1 in FIG. 16) to the right.

Subsequently, image data of the light receiving element that receivesthe light incident from the right side of the image pickup lens will bedescribed. In FIG. 17, because of the back focus, the light incidentfrom the right side of the image pickup lens is received after furtherproceeding on the left side than at the time of in-focus. That is, theimage data by the light receiving element 401 of the focus detectionpixel 410 (the first light receiving element image data C1) becomes likeimage data obtained by shifting the image data at the time of in-focusto the left. Also, the image data by the second light receiving element402 of the focus detection pixel 410 (the second light receiving elementimage data C2) becomes like image data obtained by shifting the imagedata at the time of in-focus to the left.

Next, the focus detection in the control unit 140 will be simplydescribed. First, the control unit 140 selects the two pieces of imagedata for focus adjustment (the second light receiving element image dataC2 and the first light receiving element image data D2) similarly as inFIG. 16. Then, this control unit 140 decides the movement amount of theimage pickup lens on the basis of the shift of the images between thesecond light receiving element image data D2 and the second lightreceiving element image data C2 (image interval E2) and supplies asignal for moving the image pickup lens to the drive unit 150.

FIG. 18 illustrates a phase difference detection example when the amountof light is low or small according to the first embodiment.

Herein, similarly as in FIG. 6A, it is supposed that the light amountcannot be detected by the light receiving element 401, but the lightamount can be detected by the second light receiving element 402.

Also, this FIG. 18 is the same as FIG. 17 except for the signalintensity in the image data for focus adjustment. Image data 631 isequivalent to the image data 621 of FIG. 17, and image data 632 isequivalent to the image data 622 of FIG. 17. Also, focus detectioncomparison image data 633 is equivalent to the focus detectioncomparison image data 623 of FIG. 16.

As illustrated in this FIG. 18, even in a case where the light cannot bedetected by the focus detection pixel 410 and the light receivingelement 401 of the focus detection pixel 420, the phase differencedetection can be performed on the basis of the signals of the focusdetection pixel 410 and the second light receiving element 402 of thefocus detection pixel 420.

FIG. 19 illustrates a phase difference detection example at the time oflight amount saturation according to the first embodiment.

Herein, similarly as in FIG. 6B, it is supposed that in the second lightreceiving element 402, the light receiving amount is saturated (a largepart of strength and weakness of the light amount cannot be detected),but in the light receiving element 401, the light receiving amount isnot saturated (the strength and weakness of the light amount can bedetected).

Also, this FIG. 19 is the same as FIG. 17 except for the signalintensity in the image data for focus adjustment. Image data 641 isequivalent to the image data 621 of FIG. 17, and image data 642 isequivalent to the image data 622 of FIG. 17. Also, focus detectioncomparison image data 643 is equivalent to the focus detectioncomparison image data 623 of FIG. 17.

As represented by the second light receiving element image data C2 andthe first light receiving element image data D2 of this FIG. 19, in theimage data for focus adjustment where a large part of the signals hasthe maximum value (signal upper limit value Th5), the difference of thesignals in the image data for focus adjustment is decreased. Accordingto this, a problem occurs that it is difficult to detect the shift ofthe images.

In view of the above, in a case where saturation of the light receivingamount occurs in the image data for focus adjustment of the second lightreceiving element 402, the control unit 140 selects the image data forfocus adjustment of the light receiving element 401 with the small lightreceiving amount (the first light receiving element image data C1 andthe first light receiving element image data D1). Then, this controlunit 140 decides the movement amount of the image pickup lens on thebasis of the shift of the images between the first light receivingelement image data C1 and the first light receiving element image dataD1 (the image interval E2) and supplies a signal for moving the imagepickup lens to the drive unit 150.

As illustrated in this FIG. 19, in the focus detection pixel 410 and thesecond light receiving element 402 of the focus detection pixel 420,even in a case where the light receiving amount is saturated, it ispossible to perform the phase difference detection on the basis of thesignals of the focus detection pixel 410 and the light receiving element401 of the focus detection pixel 420.

Operation Example of Control Unit

Next, an operation of the image pickup apparatus 100 will be describedwith reference to the drawings according to the first embodiment.

FIG. 20 is a flow chart illustrating a focus control procedure by theimage pickup apparatus 100 according to the first embodiment.

In FIG. 20, a procedure from the start of the focus control in a casewhere image pickup of the subject is performed to the end of the focuscontrol due to in-focus will be described. Also, herein, a case issupposed for description in which the light is picked up at such anintensity that the signal adjustment signal of one of the first lightreceiving element and the second light receiving element can be used.

First, the subject is picked up by the focus detection pixels in theimage sensor 200, and a focus adjustment signal is generated (stepS901). Subsequently, on the basis of the focus adjustment signal, imagedata for focus adjustment (image data) is generated by the signalprocessing unit 130 (step S902). It should be noted that step S901 is anexample of image pickup means described in the scope of claims.

Next, the control unit 140 determines whether among the generated imagedata for focus adjustment, the image data for focus adjustment generatedfrom the focus adjustment signal of the second light receiving elementcan be used for the calculation of the image interval (step S903). Then,in a case where it is determined that the image data for focusadjustment by the second light receiving element cannot be used (stepS903), the image data for focus adjustment generated from the focusadjustment signal of the first light receiving element is selected bythe control unit 140 (step S905). Herein, the case in which it isdetermined that the image data for focus adjustment by the second lightreceiving element cannot be used, for example, as illustrated in FIG.19, means a case in which the light receiving amount is saturated in thesecond light receiving element 402. Then, on the basis of the selectedimage data for focus adjustment by the first light receiving element,the image interval is calculated (step S906).

On the other hand, in a case where it is determined that the image datafor focus adjustment generated from the focus adjustment signal of thesecond light receiving element can be used (step S903), the image datafor focus adjustment of the second light receiving element is selectedby the control unit 140 (step S904). Then, on the basis of the selectedimage data for focus adjustment of the second light receiving element,the image interval is calculated (step S906).

Next, it is determined by the control unit 140 whether focusing iseffected on the basis of the calculated image interval (step S907).Then, in a case where it is determined that focusing is not effected(step S907), the drive amount of the image pickup lens (movement amount)in the lens unit 110 is calculated by the control unit 140 (step S908).Subsequently, the image pickup lens in the lens unit 110 is driven bythe drive unit 150 (step S909), and the flow returns to step S901. Itshould be noted that step S907 is an example of determination meansdescribed in the scope of claims.

On the other hand, in a case where it is determined that focusing iseffected (step S907), the focus control procedure is ended.

In this manner, according to the first embodiment, to set the axis L1 tobe proximate to the second light receiving element 492, by adjusting thepositions of the pair of the light receiving elements, it is possible toaccurately perform the focus adjustment.

2. Second Embodiment

According to the first embodiment, to set the example has been describedin which the optical axis of the micro lens to be proximate to one ofthe pair of the light receiving elements, the positions in the focusdetection pixel of the pair of the light receiving elements areadjusted. In this case, a general-use micro lens array where microlenses are arranged at an even interval can be used.

On the other hand, setting the optical axis of the micro lens to beproximate to one of the pair of the light receiving elements can also beperformed by adjusting the position of the micro lens with respect tothe focus detection pixel. In view of the above, according to the secondembodiment, an example of adjusting the position of the micro lens withrespect to the focus detection pixel will be described.

Configuration Example of Focus Detection Pixel

FIG. 21A is a cross sectional view and FIG. 21B is a top viewschematically illustrating an example of a focus detection pixelaccording to the second embodiment. FIGS. 21A and 21B illustrate a crosssectional configuration and a top view, respectively, of the focusdetection pixel 490 provided with a micro lens 810 as a focus detectionpixel equivalent to the focus detection pixel 410 illustrated in FIG. 3Bas an example.

FIG. 21A schematically illustrates a cross sectional configuration ofthe focus detection pixel 490 provided with the micro lens 810 accordingto the second embodiment.

According to this second embodiment, configurations except for the microlens 810 are the same as the configurations of the focus detection pixel490 illustrated in FIG. 3A, and a description thereof with respect toFIGS. 21A and 21B will be omitted. Also, FIG. 21A illustrates theposition of the micro lens 311 illustrated in FIG. 3A and the range R1incident light by broken lines as the comparison target.

The micro lens 810 is configured to collect the light incident on theimage pickup pixel 490 similarly as in the micro lens 311. This microlens 810 is arranged so that the axis (L1) passing through the center ofthe micro lens 810 is located at the end position on the side of theelement separation area 493 of the second light receiving element 492.That is, the axis L1 of this micro lens 810 does not pass through thecenter position of the focus detection pixel 490.

FIG. 21B is a top view illustrating a positional relation between themicro lens 810 and the focus detection pixel 490 according to the secondembodiment. This FIG. 21B illustrates a part of a focus detection areaaccording to the second embodiment. It should be noted that this FIG.21B illustrates positions of the micro lens 311 illustrated in FIG. 3Aby a broken line as the comparison target.

Here, a description will be given while paying attention to the positionof the micro lens 810. As compared with the micro lens 311 provided tothe focus detection pixel 490 illustrated according to the firstembodiment, the micro lens 810 is shifted in the right direction.According to this, in the focus detection pixel 490, although the centerof pixel of the focus detection pixel 490 and the center of theseparation area 493 are the same, as the position of the micro lens isshifted, the pair of the light receiving elements becomes asymmetricwith respect to the axis L1.

In this manner, this FIG. 21B illustrates that by adjusting the positionof the micro lens 311 of the focus detection pixel 490 (broken line inFIG. 21B) (moving to the right), the effect similar to the focusdetection pixel 410 can be attained.

In this manner, according to the second embodiment, by adjusting theposition of the micro lens with respect to the focus detection pixel,similarly as in the first embodiment, it is possible to efficientlyirradiate the light receiving element with one incident light among thelights subjected to the pupil division.

3. Third Embodiment

According to the first embodiment and the second embodiment, the examplehas been described in which the irradiation light on the second lightreceiving element is increased. The focus detection pixel described thusfar generates two focus adjustment signals as one focus detection pixelis provided with the pair of the light receiving elements. For thatreason, by devising a reading out method for these two focus adjustmentsignals, the speed of the focus control can be improved. In view of theabove, according to a third embodiment, an example will be described inwhich a second signal line used only for reading out one focusadjustment signal among the two focus adjustment signals is provided.

Configuration Example of Image Sensor

FIGS. 22A and 22B are schematic diagrams illustrating an example of asignal line of the image sensor 200 according to the third embodiment.

FIG. 22A illustrates the image pickup pixel 310 and the focus detectionpixel 410 connected to a signal line similarly as in the image sensor200, the image pickup pixel 310, and a focus detection pixel 530according to the third embodiment.

FIG. 22A schematically illustrates the image pickup pixel 310 and thefocus detection pixel 410 connected to the signal line similarly as inthe image sensor 200 in the conventional image pickup apparatus. In FIG.22A, one image pickup pixel 310 (center), two focus detection pixels 410(upper stage, lower stage), and a first signal line 510 are illustrated.

Also, as the image pickup pixel 310, the light receiving element 314, anFD (Floating Diffusion) 316, and an amplifier 317 are illustrated. Also,as the focus detection pixel 410, the light receiving element 401, thesecond light receiving element 402, an FD 416, and an amplifier 417.

It should be noted that the light receiving element 314 in the imagepickup pixel 310 and the first light receiving element 401 and thesecond light receiving element 402 in the focus detection pixel 410 aresimilar to those illustrated in the first embodiment, and a descriptionherein will therefore be omitted.

The FD 316 and the FD 416 are floating diffusions of the image pickuppixel 310 and the focus detection pixel 410. These FD 316 and FD 416detect charges of the light receiving elements. These FD 316 and FD 416convert the detected charges into voltages to be supplied to theamplifier 317 and the amplifier 417.

The amplifier 317 and the amplifier 417 are configured to amplify thevoltages supplied from the FD 316 and the FD 416. This amplifier 317 andthe amplifier 417 supplies the amplified voltage to the first signalline 510.

The first signal line 510 is a signal line for reading out the imagepickup signal generated by the image pickup pixel 310 and the focusadjustment signal generated by the focus detection pixel 410. The imagepickup signal and the focus adjustment signal are read out via thisfirst signal line 510 to the signal processing unit 130. For example,first, the focus adjustment signal of the light receiving element 401 inthe focus detection pixel 410 on the upper stage of FIG. 21A is readout. Subsequently, the focus adjustment signal of the second lightreceiving element 402 in the focus detection pixel 410 on the upperstage is read out, and then, the image pickup signal of the image pickuppixel 310 on the center is read out. After that, the focus adjustmentsignal of the light receiving element 401 in the focus detection pixel410 on the lower stage is read out, and finally, the focus adjustmentsignal of the second light receiving element 402 in the focus detectionpixel 410 on the lower stage is read out.

In this manner, similarly as in the image sensor 200 in the conventionalimage pickup apparatus, in a case where the focus adjustment signal ofthe focus detection pixel 410 is read out via one signal line, anecessity occurs that read out of the focus adjustment signal of thefocus detection pixel 410 is performed two times.

FIG. 22B schematically illustrates the image pickup pixel 310 and thefocus detection pixel 410 to which the signal line of the image sensor200 according to the third embodiment is connected. FIG. 22A illustratesone image pickup pixel 310 (center), two focus detection pixels 530(upper stage, lower stage), the first signal line 510, and a secondsignal line 520.

To the first signal line 510, the image pickup pixel 310 (center) andthe second light receiving elements 402 of the focus detection pixels530 (upper stage, lower stage) are connected. To the second signal line520, the light receiving elements 401 of the focus detection pixels 530(upper stage, lower stage) are connected.

Here, a difference from the image sensor 200 in the conventional imagepickup apparatus illustrated in FIG. 22A will be described. It should benoted that components except for the focus detection pixel 530 and thesecond signal line 520 are similar to those illustrated in FIG. 22A, anda description herein will therefore be omitted.

The focus detection pixel 530 is obtained by separately connecting thefirst light receiving element 401 and the second light receiving element402 of the focus detection pixel 410 illustrated in FIG. 22A to thefirst signal line 510 and the second signal line 520. This focusdetection pixel 530 is provided with an FD 533 for detecting the chargeof the light receiving element 401 to be converted into a voltage and anamplifier 534 for amplifying the converted voltage. Also, this focusdetection pixel 530 is provided with a FD 531 for detecting the chargeof the second light receiving element 402 to be converted into a voltageand an amplifier 532 for amplifying the converted voltage.

The second signal line 520 is a signal line for reading out the focusadjustment signal generated by the light receiving element 401 in thefocus detection pixel 530. This second signal line 520 takes out thefocus adjustment signal of the light receiving element 401simultaneously at a timing when the first signal line 510 takes out thefocus adjustment signal of the second light receiving element 402 of thefocus detection pixel 530.

In this manner, according to the third embodiment, by providing thesecond signal line 520, the time used for the supply of the focusadjustment signal to the signal processing unit 130 can be shortened.According to this, the time used for the generation of the image datafor focus adjustment is shortened, and it is possible to shorten thetime used for the focus control.

In this manner, according to the embodiment, by increasing the lightreceiving amount in either one of the light receiving elements of thepair of the light receiving elements and decreasing the light receivingamount in the other light receiving element, it is possible to improvethe accuracy of the focus adjustment.

Although modifications and changes may be suggested by those skilled inthe art, it is the intention of the inventors to embody within thepatent warranted hereon all changes and modifications as reasonably andproperly come within the scope of their contribution to the art.

Also, the processing procedure described in the embodiments may begrasped as a method including these series of procedures and also may begrasped as a program for causing a computer to execute these series ofprocedures or a recording medium storing the program. For this recordingmedium, for example, a CD (Compact Disc), an MD (MiniDisc), a DVD(Digital Versatile Disk), a memory card, a Blu-ray Disc (Blu-ray Disc(registered trademark)) or the like can be used.

What is claimed is:
 1. An image pickup apparatus, comprising: (A) afirst pixel region including (1) a first lens with an optical axis, (2)a first light receiving area positioned to receive light via the firstlens, (3) a second light receiving area positioned to receive light viathe first lens, and (4) an insulating area disposed between the firstlight receiving area and the second light receiving area; (B) a secondpixel region including (1) a second lens, and (2) a third lightreceiving area positioned to receive light through the second lens; and(C) a signal processing unit configured to (1) generate first datacorresponding to an electric signal from the first light receiving area,and (2) generate second data corresponding to an electric signal fromthe second light receiving area, wherein, the first light receiving areaand the second light receiving area are positioned asymmetrically withrespect to the optical axis, the optical axis intersects the insulatinglayer of the first pixel region at other than a midpoint between thefirst light receiving area and the second light receiving area, and thesecond pixel region does not include light receiving areas separated byan insulating area.
 2. The image pickup apparatus according to claim 1,wherein the insulating area of the first pixel region is configured toelectrically separate the first light receiving area and the secondlight receiving area.
 3. The image pickup apparatus according to claim1, further comprising a floating diffusion which is configured toreceive the electric signal of the first light receiving area and theelectric signal of the second light receiving area.
 4. The image pickupapparatus of claim 1, wherein an edge of the insulating area of thefirst pixel region is disposed on the optical axis of the first lens. 5.An image pickup apparatus, comprising: (A) a first pixel regionincluding (1) a first lens with an optical axis and (2) a plurality ofseparated light receiving areas positioned to receive light via thefirst lens; (B) a second pixel region including (1) a second lens and(2) another light receiving area positioned to receive light via thesecond lens; and (C) a signal processing unit configured to (1) generatefirst data corresponding to an electric signal from one of the pluralityof the light receiving areas of the first pixel region and (2) generatesecond data corresponding to an electric signal from another of theplurality of light receiving areas of the first pixel region, wherein,the plurality of light receiving areas of the first pixel region areseparated by an insulating area, the plurality of light receiving areasof the first pixel region are positioned asymmetrically about theoptical axis, the optical axis is at other than a center point betweenthe plural light receiving areas of the first pixel region, and thesecond area does not include light receiving areas separated by aninsulating area.
 6. The image pickup apparatus according to claim 5,wherein the plurality of light receiving areas of the first pixel regioninclude a first light receiving area and a second light receiving area.7. The image pickup apparatus according to claim 6, wherein theinsulating area of the first pixel region is configured to electricallyseparate the first light receiving area and the second light receivingarea.
 8. The image pickup apparatus according to claim 6, furthercomprising a floating diffusion configured to receive the electricsignal of the first light receiving area and the electric signal of thesecond light receiving area.
 9. The image pickup apparatus of claim 5,wherein an edge of the insulating area of the first pixel region isdisposed on the optical axis of the first lens.
 10. An image pickupapparatus, comprising: (A) a first pixel region including (1) a firstlens and (2) a first light receiving area and a second light receivingarea configured to receive light through the first lens; (B) a secondpixel region including (1) a second lens and (2) a third light receivingarea configured to receive light through the second lens; (C) a signalprocessing unit configured to (1) generate first data corresponding toan electric signal from the first light receiving area and (2) generatesecond data corresponding to an electric signal from the second lightreceiving area, (D) a lens unit with in image pickup lens; and (E) acontrol unit configured to calculate a shift amount of a focus accordingto the first data and the second data supplied from the signalprocessing unit, wherein, the first light receiving area and the secondlight receiving area are separated by an insulating area, the secondpixel region does not include any light receiving areas separated by aninsulating area, and the control unit is configured to calculate amovement amount of the image pickup lens of the lens unit according tothe shift amount.